Fix duplicate import removal for imports_granularity="Module"

src/imports.rs

@@ -631,6 +631,7 @@ impl UseTree {
         if let UseSegmentKind::List(list) = last.kind {
             let mut list = list.into_iter().map(UseTree::normalize).collect::<Vec<_>>();
             list.sort();
+            list.dedup();
             last = UseSegment {
                 kind: UseSegmentKind::List(list),
                 style_edition: last.style_edition,
@@ -827,6 +828,7 @@ fn merge_rest(
         UseTree::from_path(b[len..].to_vec(), DUMMY_SP),
     ];
     list.sort();
+    list.dedup();
     let mut new_path = b[..len].to_vec();
     let kind = UseSegmentKind::List(list);
     let style_edition = a[0].style_edition;
@@ -891,6 +893,7 @@ fn merge_use_trees_inner(trees: &mut Vec<UseTree>, use_tree: UseTree, merge_by:
     }
     trees.push(use_tree);
     trees.sort();
+    trees.dedup();
 }
 
 impl Hash for UseTree {

tests/source/issue-6243.rs

@@ -0,0 +1,4 @@
+// rustfmt-imports_granularity: Module
+
+use risingwave_batch::executor::{BoxedExecutor, JoinType};
+use risingwave_batch::executor::{BoxedExecutor, JoinType};

tests/target/issue-6243.rs

@@ -0,0 +1,3 @@
+// rustfmt-imports_granularity: Module
+
+use risingwave_batch::executor::{BoxedExecutor, JoinType};

tests/target/multiple.rs

@@ -16,11 +16,7 @@ extern crate foo;
 extern crate foo;
 
 use std::cell::*;
-use std::{
-    self, any, ascii, borrow, borrow, borrow, borrow, borrow, borrow, borrow, borrow, borrow,
-    borrow, borrow, boxed, boxed, boxed, boxed, boxed, boxed, boxed, boxed, boxed, boxed, char,
-    char, char, char, char, char, char, char, char, char,
-};
+use std::{self, any, ascii, borrow, boxed, char};
 
 mod doc;
 mod other;